The Inside of Me -- The Parts I
Can't See

Bones:

The framework inside
of me is called my skeleton. My skeleton is made
up of 206 bones. Without my bones, I'd be squishy
like a jellyfish and I wouldn't be able to move around.
When I was first born, I had over 300 bones, but as I
grew up some of the bones attached together to form
larger bones. By the time we're fully grown, we
only have 206 bones!

Our bones do four
important things: they provide stability to our
bodies, they give strength so we can carry weight, they
manufacture our red blood cells and they provide
protection to other parts of our insides. One of
the boniest parts of our body is our head -- the group
of bones in our head is called our skull. We have
so much bone in our skull to protect a very important
part of us: our brain.

Our bones have a lot
of a mineral called calcium in them. Drinking milk
provides us with calcium to keep our bones strong.
The outside of our bones are very hard, but they are
softer on the inside. The soft inside of our bones
is called our bone marrow. It is the marrow in our
large bones that makes our red blood cells.

Each place where our
bones meet and bend is called a joint. The bones
in our jaw and in our fingers have hinge joints.
These let our fingers pinch together and hold things.
In our hips, we have ball and socket joints. These
let our hips move all different ways... Dance, baby,
dance! The joints in our spine are called slide
joints. We even have joints in our bodies that
don't move at all -- these are called fixed joints like
the ones in our heads.

Our bones come in all
shapes and sizes. The biggest one is the bone in
our leg -- it is called the femurs. The smallest
bone is one of the three bones in our ear -- it is
called the stirrup. The other bones in our ear are
called the hammer and the anvil -- they're very small
too. As we get older our bones get bigger.
This is how we grow!

Muscles

Our muscles work together
with my bones to allow us to move. We have more
than 650 muscles in our body!

Muscles are like elastic
bands, they stretch out long and then snap back short
again. Muscles work together in groups -- as some
stretch out others tighten up, allowing us to move our
bodies around. For example, our tricep and bicep
muscles work together to flex our arm. When you
bend your arm, your bicep muscle gets short and your
tricep muscle gets long. When you straighten your
arm, your bicep muscle gets long and your tricep muscle
gets short.

Many of our muscles are
attached to our bones. The part that attaches them
is called a tendon. These are the muscles that
help me move. We also have muscles that do other
things. Our heart is a muscle that pumps blood
through our body. There are muscles in our stomach
that help us digest our food. There are muscles in
our chest that help us breathe. These muscles are
not attached to bones and do not have tendons.

The muscles attached to our
bones tend to be voluntary muscles -- we have to think
and decide to move them... We can stop them and start
them. The other muscles tend to be involuntary
muscles -- our heart pumps and our stomach digests food
without us ever thinking about it. We can't
"decide" to stop using these muscles.

If we don't use our muscles,
they grow weaker. It's important to move around
and get some exercise every day to keep our muscles
strong and healthy. When we use our muscles they
get warm, so if you're ever cold in the winter move
around and it will warm you up!

My favourite muscles are the
ones in my face. They let me smile and wink and
make funny faces! Did you know it takes 43 muscles
to frown but only 17 muscles to smile?

Heart and Blood

Our heart is the
strongest muscle in our body. It pumps our blood
all over our body through thousands of little tubes
called veins and arteries. It take about a minute
for one drop of our blood to get to all parts of our
body and then back to our heart again. If you put
your hand on your chest, you can feel your heart
pumping! If you want to feel how fast your heart
is beating, you can feel it in your chest, your wrist or
your neck. Feeling the heart beat is called the
pulse. Can you find your pulse?

Our heart is about the same
size ar our closed fist. The right side of the
heart receives blood from the rest of our body and pumps
it into our lungs where oxygen is added to the blood.
The left side of the heart receives blood full of oxygen
from the lungs and pumps it through the body, delivering
the oxygen to all of the cells.

The blood leaving your
heart is carried in arteries. It is clean and
travels to the different parts of our body carrying
oxygen from my lungs to the cells of my body. As
it travels, my blood picks up waste -- carbon dioxide --
which it delivers to be cleaned. The blood
carrying waste travels through veins.

It is the red blood
cells that carry oxygen to feed cells and carbon dioxide
to be cleaned. My blood also contains white blood
cells. I think these are the super heroes of my
body. White blood cells fight off germs and
diseases like the flu and help keep me healthy.

Our bodies have
between 2 and 4 litres of blood. If we cut
ourselves and lose some of our blood our bodies will
produce more. It is the marrow in our large bones
that make new blood cells. In the time it takes
for me to count to 20, my bones can make 10 million new
blood cells!

Lungs

When we breathe, we
take air in through our nose. The moistness and
tiny hairs in our nose catch dust and germs from the air
and help keep our insides clean. Once past our
nose, the air travels down a tube in our throat called
the trachea down into my lungs.

Underneath of our
lungs is a strong muscle called the diaphram. This
muscle moves our chest in and out. When our chest
moves out, we breathe fresh air in -- this fresh air
contains oxygen which my body needs. When our
chest moves in, we breathe used up air out -- this used
air contains carbon dioxide which is waste our body
produces. This muscle is mostly involuntary (it
moves without us thinking), but we are able to control
it a little. We can decide to take a deep breathe
in or we can decide to hold our breathe for a little
while.

There is a special
group of bones in my body to protect my lungs and my
heart. These bones are called my ribs and they are
arranged like a cage to protect my lungs and heart.

Brain and Nervous
System

Our brains are in
charge of giving orders to the rest of our bodies.
Our brain is inside our skull in our heads. It
makes our bodies move, it lets us think, feel and
remember and it keeps our involuntary muscles like our
hearts working.

Inside our bodies are
thousands of nerves that carry messages from our brain
to the other parts of our bodies. Nerves from our
eyes, ears, nose, tongue and skin carry the information
our five senses collect for us to our brain -- what do
we see, hear, smell, taste and feel. With this
information, our brain tells us about the messages and
we make decisions and have feelings and thoughts.

The most important
path for messages between the brain and the rest of our
bodies is through the spinal cord. The spinal cord
is a bundle of nerves protected by the spine.
These messages travel very quickly so that we can react
to the world around us.

My brain is where I
think and feel. I figure out puzzles in my brain.
I feel happy or sad inside my brain. My brain is
where I get scared or come up with a new idea or play
make believe.